The present application relates to a shaped article which includes titanium dioxide in a rutile form and which is suited to use as a catalyst carrier and to a method for forming the shaped article. It finds particular application in connection with a catalyst carrier in which at least about 80% of the titanium dioxide is in the rutile form that is particularly useful in hydrocarbon conversion processes.
Titanium dioxide (titania) based carriers are widely used to support catalyst compositions that are to be exposed to elevated temperatures in use. Carrier materials are commonly produced by mixing a titania powder with a temporary binder formulation until an extrudable paste is formed, then forming the paste into the desired shape, drying the shape, and firing to burn out the temporary binder and to convert the titania to a solid stable material. The titania carrier can be obtained in the shape of pellets or individual relatively small, ring-based shaped structures, such as “wagon wheels” or any other extruded shapes with constant cross-sections (as a result of extruding a continuous rod and then cutting the rod into pellets of the desired size) or large honeycomb monoliths. During firing, the titania changes phase from the amorphous phase to the anatase form (octahedral). Then, above about 800° C., it begins to transform to the rutile form.
While high firing temperatures can yield materials with good attrition resistance and corrosion resistance, the high firing temperatures are also associated with low surface areas making the materials less suited for catalyst supports.